Researchers working with mousepox virus
have created a recombinant virus capable of escaping the effects of prior immunization with vaccinia virus (22).
In the first study, researchers from Australia inserted the mouse IL-4 gene into the mousepox virus
with the aim of sterilizing the mice as a means of pest control.
The possibility that researchers could genetically manipulate the natural enemies of non-native species to kill them faster and better, thus protecting the "natural" environment, attracted public notice in 2001, when a team of virologists, seeking to control non-native rodents in Australia, announced that it had had added an interleukin-4 gene, which suppresses the immune response, to ectromelia or mousepox virus
For example, modified mousepox virus
with an interleukin-4 gene was shown to induce unexpected lethality in mice usually protected from mousepox via vaccination (6).
In February 2001, Ron Jackson and his colleagues at the Pest Animal Control Cooperative Research Center (CRC) and National University in Australia inadvertently engineered a deadly strain of mousepox virus